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Cytosolic low molecular weight acid phosphatase (ACP1) is a high polymorphic phosphotyrosine-protein-phosphatase involved in signal transduction. In NIDDM subjects we have found that ACP1 genotype is a highly significant predictor of retinopathy, suggesting that genetic variability of signal transduction may have an important role in the susceptibility to this complication. Adenosine deaminase, ABO blood groups and several clinical variables have been also considered. The results point out the importance of interactions between genetic systems. Among non-genetic variables dislipidemia and treatment with insulin are significantly associated with retinopathy.

The relationship between human placental alkaline phosphatase (PLAP) genotype and birth weight is investigated in a sample of white, black and Puerto-Rican new-born infants from New Haven, Connecticut (total 710 subjects). Black and Puerto-Rican infants show a higher incidence of growth retardation and a higher frequency of ALPp*1/*1 genotype as compared to whites. The proportion of newborns with a low birth weight (below the 10th percentile) is lower in infants with ALPp*1/*1 genotype than in those with other PLAP genotypes, especially among non-whites. It is argued that the higher frequency of ALPp*1 allele among non-whites might be, at least in part, a consequence of their adaptation in the past to environmental conditions adverse to optimal intrauterine development.

Low molecular weight acid phosphatase encoded by the highly polymorphic locus ACP1 is a member of the protein-tyrosin phosphatase family (PTPases) which plays an essential role in the control of receptor signalling through phosphotyrosine pathways. Recent experiments have shown that purified rat liver ACP, corresponding to human ACP1, is able to hydrolyze a phosphotyrosine-containing synthetic peptide corresponding to the 1146-1158 sequence of the human insulin receptor, and shows a high affinity for it. This prompted us to analyze the degree of glycemic control in relation to ACP1 genetic variability in a sample of 214 diabetic pregnant women including IDDM, NIDDM and gestational diabetes. The ACP1 genotype was also determined in 482 non-diabetic pregnant women. In diabetic women glycemic levels in the last trimester of pregnancy appear to be significantly associated with the ACP1 genotype, and correlate positively with ACP1 enzymatic activity. The data suggest that quantitative variations of ACP1 may influence the clinical manifestations of diabetic disorders, and call for further studies on the role of this enzyme in the modulation of insulin-receptor phosphotyrosine pathways.

Human red cell acid phosphatase (ACP1) is a polymorphic enzyme closely related to cytosolic low molecular weight acid phosphatases, a protein family broadly conserved among eukaryotes. Two different functions have been proposed for ACP1: flavin mononucleotide (FMN) phosphatase and phosphotyrosine phosphatase (PTPase). Given that genetic variants of ACP1 activity are common, the enzyme could have a role in regulating a large spectrum of cellular functions and, in turn, disease susceptibility. In the present paper we report a study of ACP1 genetic polymorphism in 1088 normal subjects and in 1267 subjects from the population of Rome admitted to hospital for a number of common diseases. All ACP1 parameters investigated show highly significant differences among samples, suggesting that the enzyme may have a significant role in some of the diseases considered. In particular, consistent associations of ACP1 with developmental disturbances and with hemolytic favism have been observed. In the majority of diseases showing association with ACP1, only one of the two ACP1 isoforms, f and s, is involved, supporting the hypothesis of a functional differentiation between the two enzymatic fractions.

A total of 203 couples with unexplained habitual abortions and 364 consecutive normal puerperae along with their live-born babies were studied. The analysis of wife-husband joint ABO blood group distribution in couples with habitual abortion showed an excess of A incompatible mating type and a defect of B incompatible type as compared with expected proportions assuming random mating. The joint wife-husband ABO blood group distribution was further analysed in relation to the adenosine deaminase (ADA) genotype. A defect of O-A and A-O couples when the wife carries the ADA*1/*1 genotype and the husband carries the ADA*2 allele, and a defect of O-O and A-A when the wife carries the ADA*2 allele were observed. In the sample of normal puerperae, analysis of the joint mother-newborn ABO distribution in relation to the ADA genotype showed a pattern similar to that observed in couples with habitual abortion, i.e. there is a defect of O-A and A-O when the mother carries the ADA*1/*1 genotype and the newborn carries the ADA*2 allele and a defect of O-O and A-A types when the mother carries the ADA*2 allele. Altogether the data suggest an early loss of O-A and A-O zygotes when they carry the ADA*2 allele and an early loss of O-O and A-A zygotes when the mother carries the ADA*2 allele resulting in a deficit of these zygotic classes among both spontaneously aborted fetuses and live-born infants. The pattern of association observed in the mother-fetus type O-A (incompatible according to conventional terminology) appears similar to that observed for the reciprocal A-O type (compatible according to conventional terminology). Therefore strictly conventional immunological mechanisms cannot explain the whole pattern of associations. Cell to cell intereactions involving ABO antigens may have an important role at implantation: ADA, through the control of local adenosine concentration, could modulate these interactions influencing the probability of successful implantation.

The pattern of ACP1-ADA association in 12 Sardinian villages is dependent on altitude, suggesting that genetic and/or environmental factors may influence the interactions between the two systems. This may explain the variability of the association observed in human populations.

Ninety-nine pregnant women with insulin-dependent diabetes mellitus, 83 women with gestational diabetes, and a control sample of 315 nondiabetic consecutive puerperae have been studied along with their newborn infants. Neonatal macrosomia is less frequent among diabetic mothers with phosphoglucomutase (PGM1) genotype PGM1*1/*2 than among mothers with other PGM1 genotypes. In gestational diabetes the association is more evident among younger women than among older women. Diabetic women with the PGM1*1/*2 genotype show a reduced proportion of heterozygous PGM1*1/*2 offspring. The phenomenon is much more evident among women under 28 years of age and does not depend on the quality of metabolic control. The data suggest that when both mother and fetus share the PGM1*1/*2 genotype, the deleterious effects of a diabetic environment on fetal development are more severe, leading to an early loss of zygotes. This may contribute to a decrease incidence of macromosomia among live-born infants delivered by PGM1*1/*2 mothers.

Rh E-PGM1 (phosphoglucomutase locus 1) joint genotype frequencies (chromosome 1) have been determined in 90 women with gestational diabetes mellitus (GDM) and in 140 pregnant women with preexisting insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM). The pattern of Rh E-PGM1 association differs among types of diabetes. The distortion of the pattern tends to assume opposite values in GDM and NIDDM and this is particularly evident in PGM1*2,2 subjects. The proportion of PGM1*2,2 subjects homozygous for the Rh e allele is higher in GDM than in IDDM and NIDDM. IDDM women show an intermediate proportion and NIDDM women show the lowest proportion of this genotype. The opposite pattern is observed among PGM1*2,2 subjects carrying the Rh E allele. Genotype frequencies of the hypervariable region flanking the insulin gene (chromosome 11) have been determined in 77 women with GDM, in 52 pregnant women with preexisting diabetes (IDDM and NIDDM), and in 62 normal adults. In GDM and NIDDM subjects the frequencies are similar. In IDDM women the frequency of homozygotes for the class 1 allele is higher than the frequency found in GDM and NIDDM women. The data suggest a possible genetic basis for the differentiation of a subclass of GDM from both IDDM and NIDDM.

Haptoglobin (Hp) development during the neonatal period has been studied in 325 newborn infants from normal pregnancies and in 242 infants from diabetic mothers. In infants from diabetic mothers Hp development is delayed as compared to infants from normal pregnancies. This delay is associated with a change in the pattern of relationship between Hp development and the polymorphism of acid phosphatase (ACP1) (an enzyme which shows phosphotyrosine phosphatase (PTPase) activity). In infants from normal pregnancies who show ACP1 phenotypes with the highest activity, the appearance of Hp is accelerated as compared to other infants. In contrast, infants from diabetic pregnancies who have ACP1 phenotypes with the highest activity, show delayed Hp development.

The study of 230 diabetic mothers along with their newborn babies has shown that foetal macrosomia is associated with two specific genomic sites: phosphoglucomutase locus 1 (PGM1)-Rhesus blood group (Rh) linkage group (chromosome 1) and HindIII restriction fragment length polymorphism (RFLP) linked to insulin-like growth factor 1 (IGF1) (chromosome 12). In PGM(1)2-1 mothers carrying the E allele, there is a proportion of 8.7% of macrosomic newborns as compared with 39.6% in mothers with other genotypes. The relationship between the maternal PGM1-RhE genotype and neonatal macrosomia does not depend on the type of diabetes. The proportion of macrosomic infants is much lower among newborns carrying the IGF1HS allele of the HindIII RFLP linked to IGF1 (20%) than among IGF1F/IGF1HF newborns (55%).

Low activity genetic variants of acid phosphatase (ACP1) are positively associated with extreme body mass deviations in obese subjects. The same pattern has been found in non-diabetic children, in diabetic pregnant women, and in non-diabetic adult subjects. Low activity variants of ACP1 also show a positive association with family history of obesity, supporting the hypothesis of an enhancing action of these variants on expressivity of obesity.

Phenotypes of acid phosphatase with low enzymatic activity (ACP1 A and BA) are correlated with the highest degree of body mass increase observed in a sample of obese children. Since acid phosphatase probably functions as a flavin-mononucleotide phosphatase, differential modulation of flavo-enzyme activity and energy metabolism due to acid phosphatase genetic variability may explain the observed association.

Blood samples from 718 unrelated individuals born in municipalities of the 'Alto Maceratese' region in central Italy were examined for adenosine deaminase (ADA). The allele frequencies for ADA*1 and ADA*2 were 92.48 and 7.45%, respectively. One case of the rare ADA 5-1 phenotype was observed. The observed phenotype distribution agreed well with the one expected assuming a Hardy-Weinberg equilibrium. Enzyme activity was measured in red blood cells from individuals with different phenotypes. The relationships between the enzyme activity of the phenotypes was found to be ADA 1 greater than ADA 2-1 greater than ADA 2 greater than ADA 5-1.

The pattern of associations between maternal phosphoglucomutase locus 1 (PGM1) and foetal macrosomia in diabetic pregnancy has been compared with that observed in normal pregnancy. In diabetic pregnancy a substantial increase of macrosomic infants, as compared to normal pregnancy, is observed only among women homozygous for PGM1(1) allele. Also neonatal hypoglycemia is much more frequent in newborns from PGM1(-1) mothers than in newborns from other mothers. Since enzymatic activity of PGM1(-1) phenotype is lower as compared to other PGM1 phenotypes, this may influence glycaemic level and/or its stability in diabetic pregnant women with unfavourable effects on the metabolic and developmental patterns of the foetus.

We investigated possible relations among four common neonatal manifestations of diabetic pregnancy (macrosomia, hypoglycemia, hypocalcemia, jaundice) and four enzyme polymorphisms (PGM1, ADA, AK1, ACP1 in a sample of infants born of diabetic mothers. The pattern of associations observed between the two sets of variables is consistent with known differences in enzymatic activity within phenotypes of each system, suggesting that low enzymatic activity may have unfavorable effects on fetal development and on adaptability of the neonate to the extrauterine environment, Some of the polymorphic enzymes studied influence fetal growth in normal pregnancy as well. Analysis of relations between genetic polymorphisms and the clinical pattern of common diseases may provide a better understanding of the genetic basis of the clinical variability of diseases within and between human populations.